London Cycle Hire bicycle in a docking point in Sloane Avenue, Knightsbridge. Photograph: Teri Pengilley

Ken Livingstone has pledged to bring the capital's cycle hire scheme within the scope of the Freedom Pass that allows older and disabled people free use of most public transport. His announcement comes in advance of tomorrow's (Tuesday's) first hustings of the mayoral election campaign, which will be hosted in Euston by Age UK. Such ruthless timing.

There's a particular logic to the Labour mayoral candidate's idea given that, despite its being sponsored by Barclays, the hire scheme introduced by his Tory rival Boris Johnson has become another mode of tax-payer subsidised public transport, just like the buses and the Underground. That's because it's losing money, of course. Transport for London (TfL) estimates the current annual cost of operating the scheme to be about £15 million a year, which will increase to about £20 million once phase two - expanding the territory covered by the scheme eastwards to Bow - opens for business from 8 March.

Last October the Evening Standard's Ross Lydall reported that TfL was anticipating only £7 million in revenue from the scheme by the end of this financial year. From MayorWatch we now learn that Tower Hamlets is having to stump up cash it was originally given by TfL to fund its own local projects in order to help pay for the scheme's expansion on its patch.

At this point it would be remiss not recall a few words from page 32 of Boris's 2008 transport manifesto:

We will broker a deal with a private company to bring thousands of bikes to the capital at no cost to the taxpayer.

That cruel barb hurled, what makes Ken think his own plan stacks up? The Freedom Pass is funded by London's local authorities and managed by them too. Wouldn't he have to ask them nicely first? Yes he would. But he claims that wouldn't be a problem because, he says, the total cost would be less than £250,000 a year, implying that this would be a small price to pay for "encouraging and enabling" more older Londoners to cycle. What will Boris make of that?

Two further questions come to mind. One, how many older Londoners really want to cycle in the busy parts of town? Two, has Ken himself yet learned how to ride a bike?

Sign up for the Guardian Today

Our editors' picks for the day's top news and commentary delivered to your inbox each morning.